Cloud-Native Microservices With Kubernetes - 2nd Edition

Post-Deployment Checks: Status, Events, and Logs

After creating the Deployment, it's always a good idea to check the status of the different objects we created, the system events, and the logs of the application.

To do this, we can start by checking the status of the Deployment, ReplicaSet, and Pods using the kubectl get command:

# Check the status of the Deployment
kubectl get deployment -n stateless-flask

# Check the status of the ReplicaSet
kubectl get rs -n stateless-flask

# Check the status of the Pods
kubectl get pods -n stateless-flask

Let's take a closer look at the output of kubectl get pods -n stateless-flask:

NAME                               READY   STATUS    RESTARTS   AGE
stateless-flask-74854dc7f5-8j6qs   1/1     Running   0          2m58s
stateless-flask-74854dc7f5-bwvnv   1/1     Running   0          2m58s
stateless-flask-74854dc7f5-xfw68   1/1     Running   0          2m58s

• The NAME column shows the names of the Pods. Each Pod name is a combination of the Deployment name, a unique identifier for the ReplicaSet, and a unique identifier for the Pod itself: --.

• The 1/1 in the READY column indicates that the Pod is running and ready to serve requests. This value means that one out of one container in the Pod is ready.

• The STATUS column shows the current status of the Pod, which should be Running.

• The RESTARTS column indicates how many times the Pod has been restarted, which should be 0 if everything is working correctly.

• The AGE column shows how long the Pod has been running.

We can then move on to using the kubectl describe command, which is similar to docker inspect and provides detailed information about a specific Kubernetes object.

Describe the Deployment:

kubectl describe deployment stateless-flask -n stateless-flask

Describe the ReplicaSet:

kubectl describe rs -n stateless-flask

Describe a Pod:

# Get the name of the Pod using jsonpath
POD_NAME=$(kubectl get pods -n stateless-flask -o jsonpath=